When you say DC I have to wonder what era we're talking here-- oh god, I'm over analyzing it-- but the High Fantasy of New DnD seems more Silver Age-- "Oh we just popped in to the Earth-2, I mean the Feywild..."-- whereas Old DnD's gritiness seems more in line with what I expect from Marvel.

DC is a great big mess of ideas and tones and genres strung together by the thinnest threads of frayed continuity. It has much more in common with a sandbox full of toys than a world, so in that sense it reminds me of Zak's D&D.

Marvel? It's more accessible, and consequently often much more boring.

I would have said that DC is equivalent to all those grunky arcane miniature and naval wargames which bequeathed their mechanics to D&D, early D&D is Marvel (they swiped half the art from Doctor Strange after all), and D&D3 is Image, and D&D4 is Tokyopop.